RH精炼渣高熔点相作用浓度对粘渣的影响

Effect of Effective Concentration of High Melting Point Phases in RH Refining on Slag Sticking

为抑制RH精炼过程中熔渣中高熔点镁铝尖晶石和铁铝尖晶石相的析出以减轻浸渍管粘渣,基于分子离子共存理论,建立了CaO-SiO2-MgO-Al2O3-FeO-CaF2-MnO七元精炼渣系结构单元作用浓度的计算模型,计算了高熔点相的作用浓度,分析了熔渣组成对高熔点相作用浓度的影响.结果表明,当RH精炼渣的碱度(CaO/SiO2,ω)在4.0～5.0,CaO/Al2O3(ω)为1.5～2.0,MgO含量约10%(ω),FeO含量约17%(ω),CaF2含量不高于7.5%(ω)时,精炼渣中MgO-Al2O3和FeO-Al2O3的作用浓度处于较低水平,不足以结晶析出,因而可以减轻RH浸渍管的粘渣.模型计算结果与实验结果一致,为减轻粘渣用改质剂配方的设计提供了理论依据.

To avoid crystallization of high melting point phases in refining slag, such as MgO·Al2O3 and FeO·Al2O3, during RH refining process, a calculation model of effective mass concentration for CaO-SiO2-MgO-Al2O3-MnO-FeO-CaF2 slag system was established based on the coexistence theory of slag structure, and the influences of slag components on effective concentrations of high melting point phases were studied. The results show that when slag basicity is more than 4, CaO/Al2O3 between 1.5 and 2.0, MgO content about 10%, FeO content about 17%, and CaF2 content less than 7.5%, the effective concentrations of MgO·Al2O3 and FeO·Al2O3 are at low level, MgO·Al2O3 and FeO·Al2O3 could not be crystallized from the refming slag. In this case, the slag sticking on RH immersion tube can be reduced. The calculation results are consistant with those of experiments, which may supply the theoritical basis for devolopment of slag sticking free modifying agent of RH refining slag.